1. Field of the Invention
The present invention relates to a detergent composition, and, more particularly, to a detergent composition comprising a specific type of polymer particle, which exhibits a superior physical or mechanical washing performance, and gives a remarkably reduced irritation and minimal damage to the object being washed.
2. Description of the Background Art
There are detergent compositions which comprise particles with an object of promoting mechanical washing performances. Some examples known in the art are as follows:
(1) A detergent composition containing 1-15% by weight of polymer particles having a particle size of 50 .mu.m or smaller and an internal surface area of 100 m.sup.2 /g or greater. The polymers include those from divinylbenzene, styrene, or alkyl styrene, and a mixture of two or more of these polymers. A 20% or less amount of polymers prepared from acrylic acid and/or methacrylic acid derivatives may optionally be used in combination. (German Democratic Republic Patent No. 209733)
(2) A detergent composition for washing contact lens, the face, or hands which contains 0.001-25% by weight of polymer particles having a size of 0.1-10 .mu.m. Polymers may be selected from hydrophillic cross-linked vinyl polymer, and polymers of polyhydroxy methacrylic acid, acrylic acid, or poly(N-vinyllactam). (U.S. Pat. No. 4,655,957)
(3) A scrub skin cleanser containing 2.5-20% by weight of pearl powder or chips having a size of 100-500 .mu.m. (Japanese Patent Laid-open No. 13152/1981)
Among the above detergent compositions, the composition (1) has hard particles which are irritative to the skin. Too small particle sizes of this composition do not give a good detergent efficiency. The detergent composition (2) comprises polymer particles of which the average diameter is very small. This composition imparts very low irritation. Its mechanical washing performance is, however, not sufficient. In contrast, the detergent composition (3) exhibits high detergency, but imparts harsh irritation to the skin. This is because particles contained in this composition are hard and not regular in shape. They have the risk of damaging the skin surface and thus are not suitable for use as a component of detergents for washing skin.
As can be seen in these detergent compositions, conventional techniques could not satisfy the detergency and non-irritation at the same time. The one can only be satisfied at the sacrifice of the other. This has been the problem which has needed to be solved in conventional detergent compositions.
In view of this situation, the present inventors have conducted extensive studies concerning the relationship between the characteristics of polymer particles and their detergency. As a result, the inventors have found that detergent compositions comprising polymer particles having a suitable modulus of elasticity and a specific particle size could surprisingly exhibit superior detergency without imparting irritation and damage to the object to be washed, and that, if a germicide is incorporated in addition to such polymer particles, sterilization effects on the object to be washed by the detergent composition were greatly enhanced.